That book is too old to be useful for practical applications today, but it contains a lot of useful historical information.

It is not missing most of modern cryptography, it misses only a few, albeit very important things, like post-quantum public-key algorithms, memory-hard functions for password-based algorithms, and integrity-verification algorithms with intrinsic encryption (for the latter 2 classes of algorithms I am not aware of any modern cryptography book that includes a correct and complete presentation, despite their practical importance; the information about them is spread over a large number of research papers published during the last quarter of century, and one must search and read all those papers, to be well informed).

Most of the principles of modern cryptography have barely changed after 1980, even if the specific algorithms that implement them have greatly evolved, so that almost no algorithm older than AES is still useful.

For an introduction to the principles of modern cryptography the old book of Schneier is still fine, even if the specific algorithms are no longer useful.

There are much better books for someone who is already familiar with cryptography or with abstract algebra and wants to learn something that can be used in practice, but most of those are too dense for someone without good prior knowledge of mathematics or cryptography.